GMC Envoy Forum : “The drivers side headlamp died.Where can i get a deal on a replacement and how m...”

Go to Walmart or an auto parts store and buy a new bulb.  Depending on what kind you buy, a pair will cost you $10-$30.  It will tell you how to change them in your owner's manual.  I believe that you will need a 9006 or 9007 bulb, but check in the reference at the store.

Yes, 9006 and 9007 for front and rear. For the front, just pop the hood, pull the black sliding latches up vertically and you can gently lift the full headlamp assembly out toward you. Remove the black rubber seal from the rear of the headlamp assembly and reach inside to gently twist the bayonet bulb out of its socket. Be sure not to touch the new bulb with your bare fingers, as the acid on your skin will cook on the bulb glass and burn through it. Check that the bulb is working before replacing the black rubber seal and resetting the headlamp assembly back into position. Return the black metal latches downward to lock the headlamp assembly back in. The rear tail light assemblies requre a philips head (star) screw driver to remove the assembly from the vehicle body, and then to remove the rear cover of the assembly for access to the bulbs.
From memory, the bulb was about $25 from the non-genuine parts dealer at GMC.